Definitions
The definitions of the following expressions are for comprehension purposes and are non-limitative:
Dynamic network: devices in the network can be present or absent.
Evolutive network: new devices may join the network, older devices may leave the network or be rejected by it (for example when stolen).
Heterogeneous network: not all devices are able to communicate with all other devices therein, for example if one part of the network complies with standard IEEE 802.11g, another part of the network complies with standard IEEE 802.3, in which case a bridging device is needed for the communication between the parts.
Two-way connections: two devices are two-way connected when both are able to initiate communication with the other.
Community: a community is a set of devices associated with an entity, such as a single user or a group of users (e.g. a family or company services).
Community knowledge: a device associated with (also called belonging to) a community is aware of it; the device knows that it is associated with the community and it knows at least some of the other devices in the community.
Prior Art
WO 2005/057876 teaches a system that provides secure, user-friendly evolution operations and banishment of non-trusted devices in a community. Each network device stores a local representation of the community to which it belongs. The representation comprises a provable identity for itself, three lists of devices that—1) are trusted by the device, 2) are trusted by and trusts the device, and 3) are distrusted by the device. Each device is able to execute a protocol to establish trusted connections with the other devices in the network.
While this is a good solution, it needs internal clocks in the devices to work. Since it is believed that in the future more and more devices will lack internal clocks—e.g. so called smart dust—it is desirable to have the possibility to perform secure, user-friendly evolution operations for such devices. A further advantage is that it has proven possible to improve it by minimising the processing power needed to execute the protocol. The present invention presents such an improvement.